Professor Millar, in his Origin of Ranks, followed Dr. Smith on the same ground. He explained the impolicy of slavery in general, by its bad effects upon industry, population, and morals. These effects he attached to the system of agriculture as followed in our islands. He showed, besides, how little pains were taken, or how few contrivances were thought of, to ease the labourers there. He contended, that the Africans ought to be better treated, and to be raised to a better condition; and he ridiculed the inconsistency of those who held them in bondage. "It affords," says he, "a curious spectacle to observe that the same people, who talk in a high strain of political liberty, and who consider the privilege of imposing their own taxes as one of the unalienable rights of mankind, should make no scruple of reducing a great proportion of their fellow-creatures into circumstances, by which they are not only deprived of property, but almost of every species of right. Fortune perhaps never produced a situation more calculated to ridicule a liberal hypothesis, or to show how little the conduct of men is at the bottom directed by any philosophical principles." It is a great honour to the university of Glasgow, that it should have produced, before any public agitation of this question, three professors[A], all of whom bore their public testimony against the continuance of the cruel trade. [Footnote A: The other was professor Hutcheson, before mentioned in p. 49.] From this time, or from about the year 1776, to about the year 1782, I am to put down three other coadjutors, whose labours seem to have come in a right season for the promotion of the cause. The first of these was Dr. Robertson. In his History of America, he laid open many facts relative to this subject. He showed himself a warm friend both of the Indians and Africans. He lost no opportunity of condemning that trade which brought the latter into bondage: "a trade," says he, "which is no less repugnant to the feelings of humanity than to the principles of religion." And in his Charles the Fifth, he showed in a manner that was clear, and never to be controverted, that Christianity was the great cause in the twelfth century of extirpating slavery from the West of Europe. By the establishment of this fact, he rendered important services to the oppressed Africans. For if Christianity, when it began to be felt in the heart, dictated the abolition of slavery, it certainly became those who lived in a Christian country, and who professed the Christian religion, to put an end to this cruel trade.